canvas{
  position: fixed;
  top: 0;
  left: 400px;
}
.share{
  position: absolute;
  bottom: 100rpx;
  width: 70%;
  left: 15%;
  height: 100rpx;
  line-height: 100rpx;
}
.preview {
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,.9);
  position: absolute;
  z-index: 2;
}
.preview image{
  width: 70%;
  position: absolute;
  top: 10%;
  left: 15%;
  z-index: 3;
  border: 1px dashed #fff;
}
.preview button{
  width: 40%;
  position: absolute;
  bottom: 150rpx;
  left: 30%;

}
